In putting a golf ball, the golfer must determine the proper direction in which to putt the ball, align the putter head perpendicular to that direction, judge the distance and the force necessary to get the ball to the hole, and follow through with a putt that deviates in neither force nor aim from the intended stroke. This complex set of tasks is complicated by the imprecision of the human eye, including its location several feet above the playing surface and often several yards from the hole or target. Further, most golfers have a tendency to putt too hard or too soft, or to "pull" or "push" the putter with their stronger hand, thus twisting the putter during backstroke so that the putting head is not retained perpendicular to the intended path when it strikes the ball.
A variety of improvements and additions to golf putters have been devised to correct some of these human deficiencies. One such improvement is described in U.S. Pat. No. 3,019,022. This patent discloses a golf putter incorporating a triangular reflective prism in its head, disposed laterally behind and substantially at the level of the striking face, and extending substantially from the heel to the toe of the putting head. The reflective surface of the prism is disposed such that the image from the putting face is reflected upward towards the user. Two reticles are provided, one on each transparent surface of the prism. In operation, the golfer sights both the ball and the pin through the top of the prism, and through the means of two reticles aligns the striking face of the club so that it is perpendicular to the intended path. However, this device has the disadvantage that, because the prism forms the striking face, the ball largely obscures the pin, making location of the pin difficult.
Additionally, this device and other previous putters having similar sighting systems have suffered from the disadvantage that once the putter head has been positioned, no means exists to correct the golfer's stroke so that the putter head will remain properly aligned upon contact with the ball.
It is well known in the art that "swingweighting" a club--shifting its center of mass or changing its weight--can correct for stroke deficiencies. Shifting the center of mass toward the toe of the club can correct the tendency of a right-handed golfer to "push" the club with his left hand; shifting the center of mass toward the heel likewise corrects the tendency to "pull" the club with the right hand. Changing the weight of a club, or shifting its center of mass upward or downward, can correct the tendency to swing or putt too hard or too soft.
Several patents, including U.S. Pat. Nos. 4,962,932 and 4,828,266, have attempted to address the problem of swingweighting a putter to correct for the deficiencies of a golfer's stroke. Both patents describe a putter head incorporating a weight-receiving system such that cylindrical weights may be fixed in either end of the putter head, thus shifting the center of gravity of the putter head toward the heel or toe end, or changing the overall weight of the putter so that more force is delivered for the same stroke. Further, U.S. Pat. No. 4,695,054 describes a putter head having a removable insert in its bottom portion, in which cylindrical weights may be added or removed to achieve the same purpose. Lastly, U.S. Pat. No. 4,979,744 describes a putter head having detachable toe and heel members, which in addition to lengthening the striking face of the putter can adjust the center of gravity of the putter head toward either the toe or the heel end.
Each of these methods of swingweighting suffers from the disadvantages of clumsiness and difficulty of adjustment. It can be appreciated that few golfers have the patience to disassemble, adjust, and reassemble their putters after each stroke, in the attempt to converge on the proper swingweight combination. More importantly, none of these devices provides a means for adjusting the center of mass of a putter head both in the toe-heel direction, and either upward or downward. Finally, and most importantly, none of these devices provides a means for accurately aligning the putter head initially so that it is perpendicular to the proper path.
Thus, there remains the need for a putter having a targeting system which enables the user to easily and accurately align the putter head with the target, and a putter having a system which compensates for deficiencies in the golfer's stroke, so that the proper head alignment is preserved upon impact with the ball.